1. Field of Invention
The present invention relates to a gas generator used in a restraining device of an airbag system for a vehicle or the like.
2. Description of Related Art
A gas generator that uses a pressurized gas generally employs a structure in which an opening portion of a bottle in which the pressurized gas is sealed is closed by a closing member and the pressurized gas is discharged by rupturing the closing member during activation.
Furthermore, it is desirable that the gas generator employs such a structure that the time elapsed from activation (for example, when an ignition current flows in an electric igniter) until the start of gas discharge is decreased as much as possible and the pressurized gas can be discharged quickly (a restraining device or the like is activated quickly).
US-A No. 2006/037662 discloses a gas generator that uses a pressurized gas, in which an initiator 20 is attached to one end of a housing 16, and a projectile 22 is attached to a cylindrical body 82 filled with an ignition charge. A chamber 38 filled with a pressurized gas and the initiator 20 are separated from each other by a closure member 14, and the projectile 22 abuts against the closure member 14.
U.S. Pat. No. 7,192,052 discloses a gas generator that uses a pressurized gas, in which the gas filled in a bottle 14 is sealed by a burst disc 84 attached to an opening 82. Moreover, chamber opener assembly 90 is disposed in the burst disc 84.
The opener assembly 90 has a needle 94 at a tip end thereof. When an initiator 32 ignites to effect ignition of a gas generant pyrotechnic material 54, the opener means assembly 90 moves and the needle 94 passes through the burst disc 84. The tip end of the needle 94 is a hollow tubular member of which the periphery is inclined.